[Reactivity of the LM4 form of cytochrome P-450 from rabbit liver microsomes]

Aniline oxidation and oxidative dimethylaniline demethylation with participation of the LM4 form of cytochrome P-450 from rabbit liver microsomes were studied under different conditions: e. g. after incorporation of LM4 form into microsomes of phenobarbital- and 3-methylcholanthrene-pretreated rabbits and after incorporation of this hemoprotein into liposomes in hydroperoxide-dependent reactions. The results obtained suggest that the LM4 form of cytochrome P-450 is catalytically inactive during aniline oxidation and dimethylaniline demethylation in both cases. The absence of catalytic activity of the LM4 form of cytochrome P-450 is due to the structural peculiarities of the active site of this hemoprotein rather than to its environment.